using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics.Eventing.Reader;
using System.Drawing;
using System.Globalization;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace ElementaryMathematics
{
    public partial class Form1 : Form
    {

        private bool isAdd = false;
        private bool isSubtract = false;
        private bool isMultiply = false;
        private bool isDivide = false;

        private Int32 numRunningCorrect = 0;
        private Int32 numRunningIncorrect = 0;

        private bool hasTried = false;
        private bool isError = false;
        
        
        public Form1()
        {
            InitializeComponent();

            pnlSummary.Visible = false;
            lblNumCorrect.Text = "0";
            lblNumIncorrect.Text = "0";
            UpdateButtons();
        }

        private void groupBox1_Enter(object sender, EventArgs e)
        {
            // throw new System.NotImplementedException();
        }

        private void radioButton1_CheckedChanged(object sender, EventArgs e)
        {
            // throw new System.NotImplementedException();
        }

        private void chkSummary_CheckedChanged(object sender, EventArgs e)
        {

            if (chkShowSummary.Checked)
            {
                pnlSummary.Visible = true;
            }
            else
            {
                pnlSummary.Visible = false;
            }
            
        }

        private void button1_Click(object sender, EventArgs e)
        {
            decimal total = (numRunningCorrect - numRunningIncorrect) * 100;

            MessageBox.Show("Your Score:" +
                            "\nCorrect: " + numRunningCorrect +
                            "\nIncorrect: " + numRunningIncorrect +
                            "\nTotal Score : " + (total.ToString()+"!"));

        }

        private void ChangeOperator(string op)
        {
            isAdd = false;
            isSubtract = false;
            isMultiply = false;
            isDivide = false;

            if (op == "+")
            {
                isAdd = true;
                lblOperator.Text = op;
            }else if (op == "-")
            {
                isSubtract = true;
                lblOperator.Text = op;
            }else if (op == "*")
            {
                isMultiply = true;
                lblOperator.Text = op;
            }else if (op == "/")
            {
                isDivide = true;
                lblOperator.Text = op;
            }
            else
            {
                lblOperator.Text = "";
            }
            


        }
        
        private void rdoAddition_CheckedChanged(object sender, EventArgs e)
        {
            ChangeOperator("+");
            UpdateButtons();
            isError = false;
            hasTried = false;
        }

        private void rdoSubtraction_CheckedChanged(object sender, EventArgs e)
        {
            ChangeOperator("-");
            UpdateButtons();
            isError = false;
            hasTried = false;
        }

        private void rdoMultiplication_CheckedChanged(object sender, EventArgs e)
        {
            ChangeOperator("*");
            UpdateButtons();
            isError = false;
            hasTried = false;
        }

        private void rdoDivision_CheckedChanged(object sender, EventArgs e)
        {
            ChangeOperator("/");
            UpdateButtons();
            isError = false;
            hasTried = false;
        }

        private void btnExit_Click(object sender, EventArgs e)
        {
            Close();
        }

        private ErrorProvider ep1 = new ErrorProvider();

        private decimal Calculate(decimal a, decimal b)
        {

            decimal answer = 0;


            try
            {

                if (isAdd)
                {
                    answer = a + b;
                    hasTried = true;
                    return answer;
                }else if (isSubtract)
                {
                    answer = a - b;
                    hasTried = true;
                    return answer;
                }else if (isMultiply)
                {
                    answer = a * b;
                    hasTried = true;
                    return answer;
                }else if (isDivide)
                {
                    hasTried = true;
                    if (b != 0)
                    {
                        string newan;
                        answer = a / b;
                        newan = answer.ToString("F");
                        answer = decimal.Parse(newan);
                        return answer;
                    }
                    else
                    {
                        ep1.SetError(btnChkAnswer, "Cannot Divide by 0!");
                        isError = true;
                        answer = new decimal(null);
                        return answer;
                        
                    }
                    
                }
                else
                {
                    throw new Exception();
                }
                
            }
            catch (Exception e)
            {
                ep1.SetError(btnChkAnswer, "Calculation Error");
            }


            return new decimal(null);
        }

        private void Win()
        {
            
            lblMessage.Text = "Good Job!";
            numRunningCorrect++;
            lblNumCorrect.Text = numRunningCorrect.ToString();
        }

        private void Fail()
        {

            lblMessage.Text = "Try Again";
            numRunningIncorrect++;
            lblNumIncorrect.Text = numRunningIncorrect.ToString();
        }
        
        
        private void btnChkAnswer_Click(object sender, EventArgs e)
        {
            
            ep1.Clear();

            decimal a = 0;
            decimal b = 0;
            decimal c = 0;

            try
            {

                a = decimal.Parse(txtA.Text);

                try
                {

                    b = decimal.Parse(txtB.Text);

                    try
                    {

                        c = decimal.Parse(txtC.Text);

                        try
                        {

                            if (c == Calculate(a,b))
                            {

                                Win();
                                
                            }
                            else
                            {
                                Fail();
                            }

                        }
                        catch (Exception exception)
                        {
                            MessageBox.Show("NaN", "Error", MessageBoxButtons.OK);
                        }
                        

                    }
                    catch (Exception exception)
                    {
                        
                        ep1.SetError(txtC, "Invalid Value");
                        
                    }
                    
                }
                catch (Exception exception)
                {
                    
                    ep1.SetError(txtB, "Invalid Value");
                    
                }
                
            }
            catch (Exception exception)
            {
                
                ep1.SetError(txtA, "Invalid Value");
                
            }
            
            UpdateButtons();
            
        }

        private void txtA_TextChanged(object sender, EventArgs e)
        {
            isError = false;
            hasTried = false;
            UpdateButtons();
            ep1.Clear();
        }

        private void txtB_TextChanged(object sender, EventArgs e)
        {
            isError = false;
            hasTried = false;
            UpdateButtons();
            ep1.Clear();
        }

        private void txtC_TextChanged(object sender, EventArgs e)
        {
            isError = false;
            hasTried = false;
            UpdateButtons();
            lblMessage.Text = "";
            ep1.Clear();
        }

        private void btnClear_Click(object sender, EventArgs e)
        {
            txtA.Clear();
            txtB.Clear();
            txtC.Clear();
            
            UpdateButtons();
            ep1.Clear();
        }

        private void btnReset_Click(object sender, EventArgs e)
        {
            
            DialogResult btnDialog;
            string strResponse;

            strResponse = "Do you really want to reset all statistics?";

            btnDialog = MessageBox.Show(strResponse, "Chapter Four", MessageBoxButtons.YesNo, MessageBoxIcon.Question, MessageBoxDefaultButton.Button2);

            if (btnDialog == DialogResult.Yes)
            {
                btnClear_Click(sender, e);

                numRunningCorrect = 0;
                numRunningIncorrect = 0;
            
                UpdateButtons();
                rdoAddition.Select();

                lblNumCorrect.Text = "0";
                lblNumIncorrect.Text = "0";

                txtA.Focus();
            }
            
        }

        private void UpdateButtons()
        {

            if (txtA.TextLength > 0 && txtB.TextLength > 0 && txtC.TextLength > 0 && !hasTried)
            {

                btnChkAnswer.Enabled = true;

            }
            else
            {
                btnChkAnswer.Enabled = false;
            }

            if (hasTried)
            {
                btnShowCorrectAnswer.Enabled = true;
            }
            else
            {
                btnShowCorrectAnswer.Enabled = false;
            }
            
            if (txtA.TextLength > 0 || txtB.TextLength > 0 || txtC.TextLength > 0)
            {

                btnClear.Enabled = true;

            }
            else
            {
                btnClear.Enabled = false;
            }

            if (numRunningCorrect > 0 || numRunningIncorrect > 0)
            {

                btnReset.Enabled = true;
                btnPrint.Enabled = true;

            }
            else
            {
                btnReset.Enabled = false;
                btnPrint.Enabled = false;
            }

            // if (!isError)
            // {
            //     ep1.Clear();
            // }
            
        }

        private void btnShowCorrectAnswer_Click(object sender, EventArgs e)
        {
            
               
            ep1.Clear();

            decimal a = 0;
            decimal b = 0;
            decimal c = 0;

            try
            {

                a = decimal.Parse(txtA.Text);

                try
                {

                    b = decimal.Parse(txtB.Text);

                  
                        try
                        {

                            lblMessage.Text = "Correct Answer: " + Calculate(a, b).ToString("F");

                        }
                        catch (Exception exception)
                        {
                            ep1.SetError(btnChkAnswer, "Calculation Error");
                        }
                        
                    
                }
                catch (Exception exception)
                {
                    
                    ep1.SetError(txtB, "Invalid Value");
                    
                }
                
            }
            catch (Exception exception)
            {
                
                ep1.SetError(txtA, "Invalid Value");
                
            }
            
            UpdateButtons();
            
        }

        private void label1_Click(object sender, EventArgs e)
        {
            // throw new System.NotImplementedException();
        }
    }
}